Nature Done Wright

Crows once attacked a wood duck box in Allendale's

Celery Farm Nature Preserve.

Last month, I wrote about an unexpected whodunit in my screech owl box.

Today, I offer some answers…

In early June, a great crested flycatcher built a nest inside the large box, which has a live-streaming cam that allowed me to keep an eye on the proceedings.

   I checked the cam daily and watched as the beautiful, busy flycatcher laid three eggs and incubated them. 

   After two weeks, the chicks hatched, and I looked forward to watching them during their two-week stint as nestlings.

   Then one day I activated the videocam and  – wham! – the mother flycatcher and her brood had vanished. 

  What happened?

   My guess: The babies had likely been killed by a predator, and perhaps the mom died as well or abandoned the nest. But a mystery remained. How had the predator gotten into the box?

The box rests on a pole 14 feet off the ground. The pole has a baffle to thwart raccoons and snakes, and the box has ultra-slippery sides and a steep roof to repel pesky squirrels.

    Without the cam, I would have never known for sure if the flycatcher nested in the box, let alone had hatched three young. Because I had a cam, I also had a mystery on my hands.

   In that earlier column, I mentioned that I thought the killer must have flown into the box, and asked readers to name their prime suspects. 

   Two possible culprits sat atop my list – a screech owl and, less likely, a flying squirrel. Both have been known to raid nests. A screech owl was Suspect No. 1, since they’ve often roosted in my nestbox. I also saw a flying squirrel in the box one night last year, just before the resident screech owl killed it.

   While several readers pointed their finger at a screech owl as the culprit as well, two readers had a different theory.

    “Probably crows or blue jays,” wrote Bill Spada. “Both have been very active in my yard lately. Last year a robin made a nest in our very large holly and seemed well protected, but the fledglings were taken by crows.”  

    Dannie Kishkill wrote: “My guess is a crow or crows to feed their fledged young. The entrance to the stunning nestbox is big enough to support my theory.”

   The crow theory jogged a memory. A decade ago, when the Celery Farm Nature Preserve had wood duck nestboxes on the lake, several crows attacked the boxes during nesting season. 

   I was fortunate to document that attack (see photo). It was one of the most thrilling moments I’ve experienced in the wild – but I’m still not certain a crow could fit inside the owl box’s 3.75-inch oval hole.

   For the next year, I am weighing two options: make the nestbox entrance smaller after owl/duck nesting season or add a nestbox designed to attract great crested flycatchers.